Seven people were killed and eight injured when a helicopter carrying Turkish military personnel, their wives and children crashed in the Black Sea region of northeast Turkey on Tuesday, the Turkish armed forces has said.

The cause of the Sikorsky helicopter's crash, as it returned to the town of Giresun from a visit to military outposts in the area, could not immediately be determined, a statement on the military's website said.

However, the prime minister and one of his deputies said poor weather was responsible, rather than a militant attack. The Turkish armed forces are involved in a conflict with Kurdish militants focused in the country's southeast.

Those on board, who according to media reports included a brigadier general, had been visiting military personnel and their families at gendarmerie outposts to mark the Eid al-Fitr holiday at the end of the Muslim holy month of Ramadan.

"Unfortunately, seven people among our comrades in arms, their wives and children lost their lives and the eight injured people were immediately sent to hospitals in the region," the army said, without specifying who had died.